In the prior art, dragging-type container inspection systems appeared from the beginning of 1990s, such as large container inspection systems produced by Heimann Corp., German and British Aerospace Corp. They are in an inspection passage being capable of shielding rays, and loaded with a radiation source, which is stationary and is capable of generating high-energy X-rays, and an array of detectors, which are capable of receiving X-rays penetrating a container. A vehicle loaded with a container is dragged through the inspection passage with a dedicated dragging apparatus. Such inspection systems are very bulk, and the floor space thereof corresponds to a soccer court. They suffer from the shortcomings of large floor space for civil construction, high system engineering fabrication cost, difficult to maintain, and unable to realize random inspections in different places.
For this reason, some manufacturers at home and abroad have currently developed various vehicle-carried mobile container inspection apparatuses. The present applicant filed a Chinese patent No. 99122363.2 on Nov. 5, 1999, the title of which is “a double-vehicle mobile container detection system using an accelerator as radiation source”, wherein the detection system comprises an accelerator, a scan vehicle, and a control vehicle. The disclosure of this patent is incorporated herein by reference. It is characterized in that, a rotatable tray is mounted on a bracket of the scan vehicle, and on the tray are provided an electronic linear accelerator, a collimator acting as X-ray shielding, and a gantry frame formed by a vertical strut, a horizontal cantilever and a vertical cantilever provided with detectors. When performing detection, the control vehicle goes away from the detection site and controls the gantry frame to get in parallel across containers to be inspected.
This invention has the advantages of fast detection speed, clear imaged graphics, and the like.
Afterwards, the present inventors unified both the original scan vehicle and control vehicle into one vehicle based on the patent 99122363.2, wherein both the control apparatus and operator activity region on the original control vehicle are integrated onto the original scan vehicle. This technical solution has the advantages of relatively low system cost, flexibility and the like.
However, in said inspection system, with a detection apparatus mounted on an automobile chassis, the exhaust discharged by the vehicle will cause some pollution to the port while the scan vehicle carries the detection apparatus to move in the port or change site. With the global warm-up increasingly aggravating, requirements for automobile emissions are more and more strict. As emission requirements are elevated, existing vehicle-carried inspection systems have to make replacement to the whole set of apparatus. Furthermore, each apparatus needs to be equipped with at least a set of automobile chassis, rendering the manufacturing cost and maintenance cost relatively high.